Lift jack



Dec. 26 1939. w, JOHNSON Y 2,184,455

LIFT JACK Filed July 18, 1938 2 Sheets-Sheet l M HI)" W II INVENTOR. Wu. FEED 6. Jan/-50.

ATTORNEY.

. 26, 1939. w. s. JOHNSON LIFT JACK Filed July 18, 1938 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY.

Patented Dec. 26, 1939 unites stares LIFT JACK Wilfred G. Johnson, Elyria, Ohio, assignor to- The Colson Corporation, Elyria,

poration of Ohio Ohio, a cor- Application July 18, 1938, Serial No. 219,680

21 Claims.

This invention relates to lift jacks of the type employed with movable skids and embodies improvements in the structure and operation of the lift jack described and claimed in the Pehrsson Patent No. 1,916,850.

In the Pehrsscn jack, one of the objectionable features was the possibility of accidentally tripping the foot treadle, when the jack was operatively connected to the skid, thereby disengaging the latch mechanism and thus dropping the skid.

This possibility was further increased when the handle was latched in an upright position during that time that the operator would leave .the jack and skid unattended.

It is, therefore, an object of the present invention to provide means controlled by the position of the handle which'will prevent operation of the foot treadle thereby eliminating any possibility of disengagement between the jack and skid.

A further object of the present invention is to provide means for forcing the king pin socket about its pivotal axis, by operation of the foot treadle, to thereby permit disengagement between the jack and skid for depositing the latter in its desired location. v

A still further object of the present invention is to provide a foot actuated means to facilitate the raising of the skid by the jack when the skid is empty or lightly loaded.

A still further object of the invention is to provide a handle which is independently pivoted to thereby permit pulling of the jack at any angle between those at which the foot treadle means is rendered inoperativethereby.

Another object of the present invention is to provide means for maintaining the pivotally mounted socket member normally immovable when disengaged from the skidand simultaneously to maintain the depressible projection on the frame in close relation with the handle when the latter isin its uppermost position.

With the objects above indicated and other objects hereinafter explained in View, my invention consists in theconstruction and combination of elements hereinafter described and claimed.

Referring to the drawings:

Figure 1 is a side elevational view of a skid and jack assembly embodying the present invention.

Figure 2 is a top plan View of a jack embodying the present invention and shown on an enlarged scale.

Figure 3 is a side elevational view of the jack in Figure 2 with the near wheel removed to more clearly illustrate the structural details, the view showing the relationship of the elements when the jack is skid.

Figure 4 is also a side elevational view of the jack with the near wheel removed, but showing. the relationship of the elements when the jack is not in use or when positioned beneath the king pin on the skid for engagement therewith.

Figure 5 is also a side elevational view of the jack with the near wheel removed, showing the relationship of the elements when the jack and. skid are operatively connected, the handle in this case being shown in its raised position whereby the foot treadle means is rendered inoperative.

operatively connected to the Figure 6 is a cross sectional view in elevation of the king pin socket assembly.

In the drawings, I have illustrated one type'of lift jack embodying the present invention but it is not to be so restricted inasmuch as other adaptations will be the art. I

In Figure 1 a common and well known type of skid H] isshownwhich has a pair of rear wheels H by means of which the skid may be moved about. At the front end are a pair cfstationary legs l2 positioned upon-the opposite sides of the skid and adapted to sup-port the latter when disengaged' from the jack. Intermediate the stationary'legs i2 and at the extreme forward end 20 apparent to those skilled in is a depending king pinby which the jack and skid are operatively connectedina well known manner. I The jack comprises a metal frame assembly I3 consisting of a pair of L shapedside members l4M-' of complementary contour arranged in spacedparallel relation with the long legs l5l5 in substantially horizontal position and the short legs I 6.l6 insubstantially vertical'position-as viewed in Figure 3. The short legs l6l6 are, wider spaced than the spacing of the long legs as more clearly shown in Figure 2 and'ha've a bridging member ll adjacent their near upper portion, preferably formed integral therewith to provide rigidity and to maintain the legs in proper spaced relation.

' The outer ends of the short legs lfilfi are provided with aligned openings within which suitable bearing s Id -I8 are disposed, which bearings have lateral'fianges l9,-l9 engageable with the outer faces of the legs so as to maintain them .in proper position. The bearings may be aligned openings within which suitable bearings 2l2l are disposed, the bearings in this instance having lateral flanges 22-22 engageable with the inner faces of the legs. The bearings may be secured in any suitable manner but preferably by arc welding as at 23. To further reinforce the frame a plate 24 extends between the inner ends of the long legs Iii-l5 and is welded or otherwise secured. The outer ends of the long legs |5l5 are spread apart and a knurled roller 25 is disposed therebetween which is secured by means of welding. At the inner ends of the long legs l5l5, a spring actuated plunger housing 26 is disposed with the plunger end projecting forwardly and is secured by welding to the adjacent portion of the long legs. The housing has an inwardly extending bore within which a plunger 21 is slidably mounted and is normally urged outwardly by a coiled spring 28 disposed between the inner end of the plunger and the bottom of the bore. The plunger 27 has an axially extending stem 29 disposed centrally of the spring and projects outwardly through an opening in the end wall. A pin 30 extends through the outer end of the stem to limit the outward movement of the plunger. This long leg of the frame functions as a foot treadle for facilitating the raising of the empty or lightly loaded skid in a manner to be later described.

A shaft 3| extends through the bearings 2l2| at the lower portion of the frame and a pair of wheels 32-32 are rotatably mounted upon the opposite ends. The wheels may be of various types and sizes but preferably are rubber tired as at 33 to provide quiet operation and negligible wearupon the surface over which the loads are drawn. The wheels 3232 should preferably be of a diameter relative to that of the wheels llll on the skid so that the top of the skid is substantially in a horizontal plane thus insuring proper loading.

A king pin socket member 34 is pivotally mounted at its upper end between the bearings l 8|8 on the short legs l6l 6 and has its lower end projecting downwardly and formed with a cam face 35 on its under side. One side of the socket member 34, when positioned as shown in Figure 3, engages the plunger 21 and the opposite side is provided with a recess 36 for a purpose to be later described. A handle latch member 31 comprises spaced arms 38-38 having hooked ends 3939 and a transversely extending substantially horizontal bridging member 40 integrally connecting the opposite ends. The latch member 31 is disposed between the lateral flanges 2222 of bearing members 2l2l and the arms 38-38 are provided with aligned openings through which the shaft 3| projects and upon which it is pivotally mounted. The bridging memberS'l engages the under side of the plunger housing 26 to limit the pivotal movement of the latch member in one direction.

A dog assembly 4| comprises spaced side members 4242 of bell crank contour and have pins 43 rigidly connecting their opposite ends and maintaining the side members in spaced relation. A roller member 44 is rotatably mounted on one of the pins 43 and the dog assembly is disposed between the side arms 3838 of the latch member 36, the side members 42-42 being provided with aligned openings through which the shaft 3| projects and upon which the dog assembly is pivotally mounted. A helical twist spring 44a. encircles the shaft 3| between the side members 4242 and has its looped intermediate end por- 1 shape.

plates.

tion 45 engageable with the under side of the bridging member 40 and its outer free ends engageable with the pin 43 on the dog assembly opposite the roller 44. The spring therefore has a double function, to maintain the looped ends of the handle latch under tension and to maintain the roller end of the dog assembly under tension.

It will be noted that the roller member 44 on the dog assembly is positioned so as to engage the recess 36 on the lower end of the socket member 34 as clearly shown in Figure 3 and that this engagement is maintained by the tension of the spring 44a. At the same time the latching of the socket member in this position functions to hold the plunger 27 within its housing against its spring pressure.

To trip the dog assembly any desirable means may be employed but preferably as shown, a foot treadle actuating member 46 is disposed between the long legs l5l 5 of the frame assembly. This member 46 has a substantially flat upper surface and a centrally disposed depending reinforcing rib 41. A channel shaped extension 48 is provided about midway of the ends of the treadle member which projects outwardly a suitable distance and is connected to the latter by welding or other means. The side walls of the channel shaped extension 48 and the long legs |5--I5 of the frame assembly are provided with aligned openings to receive a transversely extending pin 49 about which the treadle member 46 pivots. Ihe treadle member 45 is normally at an angle so that its inner end is disposed beneath the pin 43 on the adjacent end of the dog assembly and its outer end exposed above the upper edges of the long legs |5l5 of the frame in a suitable position accessible to the foot of the operator. Therefore, to disengage the roller member 44 from the recess 36 on the socket member 34 it is only necessary to press. downwardly upon the outer end of the treadle 46 which moves the dog assembly about its axis thus moving the roller 44 below the end of the socket whereupon, the spring pressed plunger 21 forces the socket outwardly about its pivot and the jack and skid can then be disengaged. When so disengaged the elements assume the relationship shown in Figure 4.

In order to pull the jack about a handle assembly is provided which consists of a pair of spaced side plates 505U substantially of L The short legs 5l5l of these side plates are positioned on the outer sides of the short legs l6l6 of the frame assembly and are provided with aligned openings through which the pins 52-52 pass and upon which the side plates 50-50 are pivotally mounted. It is to be noted that while the plates and socket are pivotally mounted upon the same axis they each are capable of independent movement thereabout for a purpose to be later described. The short legs of the side plates 5Il-50 are maintained in spaced relation and reinforced by a spacer member 53, about midway between their pivotal axis and the outer end, as viewed in Figure 3, the spacer member extending transversely and having reduced screwthreaded ends which project through aligned openings provided in the side plates. Nuts '54 engage the screwthreaded ends and secure the elements in assembled relation. A rod 55 also extends transversely between the short legs of the side plates 5ll5ll, outwardly and downwardly from the spacer member 53, and has its ends riveted or otherwise secured to the This rod 55 is so located that when the plates 58-40 are moved about their pivot in a counter-clockwise direction as viewed in Figure 3, it will engage the hooked ends of the handle latch and pass thereunder into the recesses and the coiled spring ida will exert sumcient pressure to maintain the plates in this position whereby the handle will be maintained in its upperward position as shown in Figure 5. It is also to be noted that, when the handle is latched in this upright position, the axis of rod55 is slightly inwardly of the axis of the roller 44 and consequently the dog assembly is thereby rendered inoperative.

The long legs 58-53 of the side plates 5Il-50 also extend in parallelism but are spaced slightly closer together than the spacing of the short legs and taper outwardly. A handle 5? of tubular metal has a hand grip 58 at its outer end while its inner end is slightly flattened and welded or otherwise secured to a tubular member 59 positioned between the long legs Ed -56 adjacent the inner portion and upper edge. The long legs 56-56 have aligned openings to receive a bolt passing therethrough and through the tubular member 59 by means of which these members are secured in assembled relation. At the outer ends of the long legs 5656 is a collar 68 through which the tubular handle passes and is provided with reduced screwthreaded extensions which project through aligned openings in the long legs. Nuts 8| are employed to secure'the collar in rigid assembly. The side plates 5ll-58 are provided with recessed portions 6262 extending iagonally between adjacent short and long legs and have shoulders 63 and 6d at their opposite ends. These shoulders are for engagement with the bearings 2i-2i on the frame assembly to thereby limit the pivotal movement of the handle. Additionally, engagement between the shoulders G3 and the bearings 21, when the handle is in its upward position, affords rearward pushing upon the handle to back the skid and jack without possibility of disengaging the load.

As previously stated it is also desirable to prevent operation of the foot treadle, accidentally or otherwise, when the handle is in its lowered position. This is accomplished in the present instance, by providing 2. depending pin 65 on the under side of the tubular member 58 about midway or so as to be normallydisposed behind the upper end of the channel member it on the treadle member 46 as viewed in Figure 3. This relationship is indicated by the full line position of the elements and it will be obvious that any effect to depress the outer end of the treadle member will be counteracted by engagement between the pin and channel member. However, in the event it is desired to discharge the skid from the jack, the handle is raised to a position where thepin and channel member are out of operative contact, as indicated by the dot and dash lines in Figure 3, whereupon, the treadle member is free to be moved about its axis, and upon such movement by the foot of the operator, the dog assembly is moved about its pivot until the roller member M is free of the end of the socket member 34 at whichtime the socket member 34: is thrust outwardly by the spring pressed plunger 27 and the skid may be lowered to the floor upon a further upward movement of the handle.

In connecting the jack, and skid for unitary operation, the jack is moved into position to bring the socket beneath the king pin on the skid and with the elements in the relation shown in Figure 4. If there is an empty or lightly loaded skid to be raised, the handle is lowered slightly by the operator and then he places his foot upon the knurled roller on the outer end of the frame and pushes. downwardly. This movement rocks the frame about the wheel axis and raises the stationary end of the skid mov-- ing it toward the wheel axis. During this movement the roller M on the dog assembly rides around the cam face -and into the recess 3% thereby locking the socket against movement and thus preventing accidental disengagement between the jack and skid. The loaded skid may also be raised by using the handle as ,a lever in the event of heavy loads requiring a minimum of effort on the part of the operator.

The socket assembly is shown in detail in Figure 6 and comprises a body member 66, substantially circular in cross section, having its upper end slightly flared at 6? and its lower end formed with a cam face 35 of a predetermined shape. -The body member is provided with aligned bores 61 on diametrically opposite sides somewhat below the upper end by means of which the socket assembly is adapted for pivotal mounting. These bores likewise ber is further provided with bosses 69 and ill on diametrically opposite sides which have fiat parallel faces for a purpose heretofore described. A transversely extending recess H is formed in the face of the boss 69 adjacent its lower end and the cam face 35 extends from the lower edge of the recess on a generally upwardly extending arc to the lower end of the boss ill. The body member 66 has a central bore l2 extending inwardly from its outer end to about midway of its length where it communicates with a central bore 13 of smaller diameter which extends a suitable distance beyond. At the lower end of the bore 12, an annular seat it is provided while at the upper end of the bore a similar annular seat 15 of slightly larger diameter is provided, these seats being in concentric relation. A socket member EB has a circular portion fitting within but spaced from the wall of the bore and its outer end is formed with a lateral flange "it which projects over the outer end of the body member. The lower end of the socket member is reduced at 19 to fit within but spaced from the wall of the bore 3. The socket member'l'i is rotatably supported on two sets of ball bearings 80 and BI disposed in the annular grooves '15 and it respectively. The ball bearings also function as thrust bearings and the arrangement is such that a minimum of resistance is offered to the rotary movement of the socket member regardless of the load imposed. To maintain the socket member in assembled relation, the lower end 19 has a peripheral groove 82 and the body portion is provided with a screwthreaded opening to receive a screw having an extension which projects freely into the groove 82 thereby preventing accidental disengagement of'the socket member. Diametrically opposite the body portion is provided with an opening to receive a lubricant fitting for proper lubrication of the socket. The socket member is also provided with an axial bore 83 extending inwardly from its outer end of sufficient diameter to accommodate a king pin on the skid.

It will be noted that while the king pin socket assembly is free to move about its pivotal under the influence of the king pin it is otherwise maintained immovable especially as shown in Figure 4 disengaged from the skid. In this extend transversely of the cam face 35. The body memcondition the socket assembly engages the spacer member 53 while the roller member 44 on the dog assembly engages the opposite side and is so held by the tension of the coiled spring 44a.

It is believed that the foregoing description will sufiice for a clear understanding of the operation and any further detailed explanation will be unnecessary.

While I have described the preferred embodiment of the invention it is to be understood that I am not to be limited thereto inasmuch as changes and modifications may be resorted to without departing from the spirit of the invention as defined in the appended claims.

What is claimed is:

1. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower rear portion of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner end pivotally connected to said frame for independent movement about the axis of said socket member. cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket for maintaining the latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of the socket so that it is free to move about its pivotal axis, and cooperating means on said handle and treadle to prevent actuation of the latter when the handle is in its lowermost position.

2. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower rear portion of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner end pivotally connected to said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket for maintaining the latter in operative position, and a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of the socket so that it is free to move about its pivotal axis, said treadle being provided with a lateral extension projecting toward said handle and said handle being provided with a member cooperatively engageable with the lateral extension on said treadle when the handle is in its lowermost position to thereby render the treadle inoperative.

3. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower rear portion of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner. end pivotally connected to said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket for maintaining the latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of the socket so that it is free to move about its pivotal axis, cooperating means on said handle and treadle to prevent actuation of the latter when the handle is in'its lowermost position, and means on said handle operatively engageable with said dog to prevent actuation of the latter when said handle is in its uppermost position.

4. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower rear portion of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner end pivotally connected to said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket for maintaining the latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of the socket so that it is free to move about its pivotal axis, cooperating means on said handle and treadle to prevent actuation of the latter when the handle is in its lowermost position, and a spring actuated handle latch pivotally mounted about the axis of said wheels and having a rearwardly projecting hooked end portion releasably engageable with a portion of said handle when in its uppermost position to so maintain the latter, said handle being releasable by a downward movement thereof about its pivotal axis.

5. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower rear portion of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said Wheel axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner end pivotally connected to said frame for independentmovement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket for maintaining the latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring of said wheels and having a rearwardly projecting hooked end portion releasably engageable with a portion of said handle when in its uppermost position to so maintain the latter, said handle being releasable by a downward movement thereof about its'pivotal axis, and means on said handle operatively engageable with said dog to prevent actuation of the latter when the handle is in its uppermost position.

6. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted'at the lower rear portion of said frame, a king pin socket member pivotally mounted adjacent its upper.

end to the upper portion of said frame rearwardly of said wheel-axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner end pivotally connectedto said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite po sitions, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket for maintaining the'latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of the socket so that it is free to move about its pivotal axis, a spring actuated plunger on said frame engageable with the lower end of said socket and operable upon release of the latter to posie tively swing said socket about its pivotal axis to inoperative position, and cooperating means on said handle and treadle to prevent actuation of the latter when the handle is in its lowermost position.

7. In a lift jack of the character described, a

die and frame for limiting the pivotal movement on said frame and having its inner .end operatively connected to said dog for moving the latter about its pivotal axis against the springtension to release the lower end of the socket so that it is' free to move about its pivotal axis, and coop-- crating means on said handle and treadle to prevent actuation cf the latter when the handle is in its lowermost position.

8. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower rear portion of said frame, a king pinsocket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner end bifurcated and pivotally connected on oppositesides of said frame for independent movement about the axis of said socket member, a latch rod connecting the bifurcated. ends of said handle and extending transversely thereof rearwardlyof its pivotal axis, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engage able with the lower end of said socket for maintaining the latter in operative position, avmanually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for-moving the latter about its pivotal axis against the'spring tension to release the lower end of the socket so that it is free to move about its pivotal axis, cooperating means on said handle and treadle to prevent actuation of the latter when the handle is-in its lowermost position, and a spring actuated handle latch pivotally mounted about the axis of said wheels and having a rearwardly projecting hooked end portion releasably engageable with the latch rod on said handle when in its uppermost position to so maintain the latter, said handle being releasable by a downward movement thereof about its pivotal axis.

9. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower rear portion of said frame, "a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner end pivotally connected to said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said-socket for maintaining the latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of the socket so that it is free to move about its pivotal axis, means on said frame engageable with the lower end of said socket member and operable upon release of the latter to forcibly swing said socket member about its pivotal axis to inoperative position and into engagement with a stop member onsaid handle, said dog having a portion releasably engageable with the opposite side of said socket member to hold the latter normally immovable about its axis, and cooperating means on said handle and treadle to prevent actuation of the latter when the handle is in its lowermost position.

In a wheeled truck, the combination of a skid and a jack, the skid comprising a platform, a pair of wheels attached to one end thereof, a stationary support at the other end, and a depending king pin on the stationary end of the platform; and the jack comp-rising a frame,

' wheels rotatablymounted at the lower rear end of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of the wheel axis, said socket member being adapted to supportingly receive said king pin, a handle having its inner end pivotally mounted on said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, said handle when in engagement with one of said limiting means being adapted to move said frame about the wheel axis to thereby raise the end of the skid off of its stationary support by means of the cooperating king pin and socket member, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket member for maintaining the latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of said socket member so that it is free to move about its pivotal axis whereby the skid may be disengaged from the jack, andcooperating means on said handle and treadle to; prevent actuation of the latter when said handle is in its lowermost position.

11. In a wheeled truck, the combination of a skid and a jack, the skid comprising a platform, a pair of wheels attached to one end thereof, a stationary support at the other end, and a depending king pin on the stationary end of the platform; and the jack comprising a frame, wheels rotatably mounted at the lower rear end of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of the wheel axis, said socket member being adapted to supportingly receive said king pin, a handle having its inner end pivotally mounted on said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, said handle when in engagement with one of said limiting means being adapted to move said frame about the wheel axis to thereby raise the end of the skid off of its stationary support by means of the cooperating king pin and socket member, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket member for maintaining the latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of said socket member so that it is free to move about its pivotal axis whereby the skid may be disengaged from the jack, cooperating means on said handle and treadle to prevent actuation of the latter when said handle is in its lowermost position, and means on said handle operatively engageable with said dog to prevent actuation of the latter when said handle is in its uppermost position.

12. In a wheeled truck, the combination of a skid and a jack, the skid comprising a platform, a pair of wheels attached to one end thereof, a stationary support at the other end, and a depending king pin on the stationary end of the platform; and the jack comprising a frame,

wheels rotatably mounted at the lower rear endof said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of the wheel axis, said socket member being adapted to supportingly receive said king pin, a handle having its inner end pivotally mounted on said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, said handle when in engagement with one of said limitingmeans being adapted to move said frame about the wheel axis to thereby raise the end of the skid off of its stationary support by means of the cooperating king pin and socket member, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket member for maintaining the latter in operative posit-ion, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of said socket member so that it is free to move about its pivotal axis whereby the skid may be disengaged from the jack, cooperating means on said handle and treadle to prevent actuation of the latter when said handle is in its lowermost position, and a spring actuated handle latch pivotally mounted about the axis of said wheels and having a rearwardly projecting hooked end portion releasably engageable with a portion of said handle when in its uppermost position to so maintain the latter, said handle being releasable by a downward movement thereof about its pivotal axis.

13. In a wheeled truck, the combination of a skid and a jack, the skid comprising a platform, a pair of wheels attached to one end thereof, a stationary support at the other end, and a depending king pin on the stationary end of the platform; and the jack comprising a frame, wheels rotatably mounted at the lower rear end of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of the wheel axis, said socket member being adapted to supper tingly receive said king pin, a handle having its inner end pivotally mounted on said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, said handle when in engagement with one of said limiting means being adapted to move said frame about the wheel axis to thereby raise the end of the skid off its stationary support by means of the the latter about its pivotal axis against the spring tension to release the lower end of said socket member so that it is free to move about its pivotal axis whereby the skid may be disengaged from the jack, cooperating means on said handle and treadle to prevent actuation of the latter when said handle is in its lowermost position, a spring actuated handle latch pivotally mounted about the axis of said wheels and having a rearwardly projecting hooked end portion releasably engageable with a portion of said handle when in its uppermost position to' so maintain the latter, said handle being releasable by a downward movement thereof about its pivotal axis,

and means on said handle operatively engageable with said dog to prevent actuation of the latter when said handle is in its uppermost position.

14. In a wheeled truck, the combination of a skid and a jack, the skid comprising a platform,

a pair of wheels attached to one end thereof, a

stationary support at the other end, and a depending king pin on the stationary end of the pendent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, said handle when in engagement with one of said limiting means being adapted to move said frame about the wheel axis to thereby raise the end of the skid off of its stationary support by means of the cooperating king pin and socket member, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket member for maintaining the latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of said socket member so that it is free to move about its pivotal axis whereby the skid may be disengaged from the jack, a spring actuated plunger on said frame engageable with the lower end of said socket member and operable upon release of the latter to positively swing said socket member about its pivotal axis, and cooperating means on said handie and treadle to prevent actuation of the latter when said handle is in its lowermost position.

15. In a wheeled truck, the combination of a skid and a jack, the skid comprising a platform, a pair of wheels attached to one end thereof, a stationary support at the other end, and a depending king pin on the stationary end of the platform; and the jack comprising a frame having a forwardly extending projection, wheels rotatably mounted at the lower rear end of said frame, ,a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of the wheel axis, said socket member being adapted to supportingly'receive said king pin, a handle having its inner end pivotally mounted on said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, said handle when in engagement with one of said limiting means being adapted to move said frame about the wheel axis to thereby raise the end of the skid off of its stationary support by means of the cooperating king pin and socket member, said projection being manually depressible to move said frame about the axis of said wheels independently of said handle actuation to adapt the jack'for raising of light loads, a spring actuated dog pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket member for maintaining the latter in operative position, a manually operable treadle pivotally mounted onsaid frame and having its inner end operatively connected to said dog for moving the latter about its pivotal axis against the spring tension to release the lower end of said socket member so that it is free to move about its pivotal axis whereby the skid may be disengaged from the jack, and cooperating means on said handle and treadle to prevent actuation. of the latter when saidhandle is in its lowermost position.

16. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower rear portion of said frame, a. king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for: cooperative engagement with the king pin on a skid, a handle having its inner end pivotally connected to said frame for independent movement about the axis of said socket member, cooperating means on said. handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, means p votally mounted about the axis of .said wheels and having a portion releasably engageable with the lower end of said socket for maintaining the latter, in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said means for moving the latter about its pivotal axis to release the lower end of the socket so that it is .free to move about its pivotal axis, and cooperating means on said handle and treadle to prevent actuation of the latter when the bandle is in its lowermost position.

.17. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower rear portion of said frame, a king pin socket member pivotally mounted adjacent its a upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner end pivotally connected to saidframe for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, means pivotal y mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket for maintaining the latter in operative position, a manually operable treadle pivotally mounted onsaid frame and having its inner end operatively connected to said means for moving the latter about its pivotal axis to release the lower end of the socket so that it is free to move about its pivotal axis, cooperating means on said handle and treadle to prevent actuation of the latter when the handle is in its lowermost position, and means on said handle operatively engageable with said first mentioned means to prevent actuation of the latter when said handle is in its uppermost position.

18. In a lift jack of the character described, a frame having a forwardly extending projection, a pair of wheels rotatably mounted at the lower rear portion of said frame, said projection being manually depressible to move the frame about the axis of said wheels, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for cooperative engagement with the king pin on a skid, a handle having its inner end pivotally connected to said frame for independent move, ment about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, means pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket for maintaining the latter in operative position, a manually operable treadle pivotally mounted on said frame and having its inner end operatively connected to said last mentioned means for moving the latter about its pivotal axis to release the lower end of the socket so that it is free to move about its pivotal axis, and cooperating means on said handle and treadle to prevent actuation of the latter when the handle is in its lowermost position.

19. In a wheeled truck, the combination of a skid and a jack, the skid comprising a platform, a pair of Wheels attached to one end thereof, a stationary support at the other end, and a depending king pin on the stationary end of the platform; and the jack comprising a frame, wheels rotatably mounted at the lower end of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of the wheel axis, said socket member being adapted to supportingly receive said king pin, a handle having its inner end pivotally mounted on said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, said handle when in engagement with one of said limiting means being adapted to move said frame about the wheel axis to thereby raise the end of the skid off of its stationary support by means of the cooperating king pin and socket member, means pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket member for maintaining the latter in operative position, and manually operable means operatively connected to said pivotally mounted means for moving the latter about its pivotal axis to release the lower end of said socket member so that said socket member is free to move about its pivotal axis to thereby disengage the jack from the skid.

20. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower portion of said frame, a king pin socket member pivotally mounted adjacent its upper end to the upper portion of said frame rearwardly of said wheel axis and adapted for 00- operative engagement with the king pin on a skid, a handle having its inner end pivotally connected to said frame for independent movement about the axis of said socket member, cooperating means on said handle and frame for limiting the pivotal movement of said handle at extreme opposite positions, means pivotally mounted about the axis of said wheels and having a portion releasably engageable with the lower end of said socket member for maintaining the latter in elevated position, and a manually operable means operatively connected to said pivotally mounted means for moving the latter about its pivotal axis to thereby release the lower end of said socket member so that said socket member is free to move about its pivotal axis to lowered position for engagement with or disengagement from the king pin.

21. In a lift jack of the character described, a frame, a pair of wheels rotatably mounted at the lower portion of said frame, a king pin socket member pivotally mounted adjacent its upper extreme opposite positions, a dog pivotally mountedabout the axis of said wheels and having a portion releasably engageable with the lower end of said socket member for maintaining the latter in elevated position, and a manually operable means operatively connected to said dog for moving the latter about its pivotal axis to thereby release the lower end of said socket member so that said socket member is free to move about its pivotal axis to lowered position for engagement with or disengagement from the king pin.

WILFRED G. JOHNSON. 

